Perxenate
Perxenate is an anion containing xenon in its +8 oxidation state. It is one of the strongest oxidizing agents known. Perxenates are salts derived from perxenic acid (H4XeO6), which itself is only stable in strongly alkaline solutions.
Properties:
Perxenates are generally colorless or pale yellow solids. They are thermodynamically unstable and decompose slowly in solution, even in alkaline conditions, releasing oxygen gas and forming xenates or xenon trioxide. The rate of decomposition is pH-dependent, being faster in more acidic conditions.
Perxenates are powerful oxidizing agents, capable of oxidizing various metals to their highest oxidation states. In aqueous solutions, they decompose water, releasing oxygen. This strong oxidizing power is a direct consequence of xenon being in its highest possible oxidation state.
Synthesis:
Perxenates are typically synthesized by dissolving xenon tetroxide (XeO4) in strongly alkaline solutions. Xenon tetroxide itself is obtained by oxidizing xenates with ozone or fluorinating sodium perxenate. Another method involves the ozonation of xenate solutions. The synthesis often requires careful control of conditions to prevent explosive decomposition.
Structure:
The perxenate anion, XeO64-, has an octahedral structure, with the xenon atom at the center and six oxygen atoms surrounding it. The Xe-O bond lengths are relatively short, reflecting the strong bonding between the xenon and oxygen atoms.
Applications:
Due to their instability and strong oxidizing power, perxenates have limited practical applications. They are primarily used in research contexts as oxidizing agents for specific reactions or in studies investigating the chemistry of xenon compounds. They have also been used to synthesize other exotic xenon compounds.
Safety:
Perxenates are potent oxidizing agents and should be handled with caution. They can react violently with combustible materials. Solutions of perxenates are corrosive. Appropriate personal protective equipment, such as gloves and eye protection, should be worn when handling perxenates or their solutions. They are generally considered explosive hazards.